718 MICTURITION. [BOOK n. 



the urine, which in a healthy man is insignificant, though in some 

 animals, for instance the horse, it occurs in considerable quantity, 

 is largely increased during the stay in the bladder. Since there 

 are in man no goblet cells in the vesical epithelium (in the frog 

 they are present) or mucus glands in the walls of the bladder, this 

 mucus must be supplied by an abnormal metabolism of the ordinary 

 epithelial cells. 



